March 21 is the United Nations' International Day for the Elimination of Racial Discrimination.

"We're extremely excited, it was for a very good cause, we're sending a message loud and clear that everybody should be united, we're against racism and our children are holding hands and I think they're sending the message loud and clear," said English teacher Penelope Aristou.

Racism has become an issue in Greece in the last two years following a series of racist attacks on immigrants believed to be carried out by right wing extremists.

The thousands of children, who came with their teachers from schools in the Greek capital, after forming the human chain held up placards reading "I embrace the Acropolis, I embrace humanity," and sang as tourists looked on.

"I really like doing this event, because we need to show respect for everyone, it's very important," said 12-year-old Marilia Diamantopoulou.